1. Field of Invention
The present invention relates to an alternator mounted on an engine. More particularly, the present invention relates to an alternator pulley, and a mounting structure of an alternator pulley and an alternator configured to decrease belt vibration by mounting an adaptor which includes a pendulum.
2. Description of Related Art
In general, an alternator is mounted on a vehicle and generates electricity for charging a battery of the vehicle. Moreover, the alternator receives power from an engine by a connecting belt between an alternator pulley and a crankshaft pulley of the engine.
Meanwhile, the alternator pulley has greater torsional vibration than the crankshaft pulley because a rotation speed of the alternator pulley is more than twice as fast as a rotation speed of the crankshaft pulley.
FIG. 1 and FIG. 2 are schematic diagrams of a traditional alternator pulley system.
As shown in FIG. 1 and FIG. 2, FIG. 1 is a schematic diagram of a traditional solid type of alternator pulley system, and FIG. 2 is a schematic diagram of a traditional overrunning alternator decoupler (OAD) type of alternator pulley system. The traditional solid type of alternator pulley has an alternator shaft 11 made of a rigid body, so that an alternator 10 and an alternator pulley 12 are directly connected. On the contrary, the traditional OAD type of alternator pulley has the alternator shaft 21 inserted with a spring (OAD spring) therein, so that an alternator 20 and an alternator pulley 22 are connected by the spring.
Recently, the OAD type alternator pulley has been widely used because belt slip due to large vibration of the belt 13 which connects the alternator pulley 12 with the crankshaft pulley 14 occurs in the solid type of alternator pulley. The OAD type of alternator pulley has the effect of reducing an idle vibration compared to the solid type of alternator pulley because a vibration resonance point of the belt in the idle RPM range is decreased.
However, the idle vibration is only reduced in the idle RPM rather than in the entire RPM range, and a subharmonic vibration caused by nonlinearity of the spring even occurs in the idle RPM range.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.